Replacement Prop question

[Jedi]

Looking to buy a new prop for the exiting prop  #48 78118 A40 P17

I/O 5.0 Mercruiser 95 Penn yan

is that a 15x17 or 14.5x17p ? And what is the inside diameter?

Thinking about going steel prop (3blades)if I can find one in the $300 range 🤣 If not going with a good aluminum prop. 

lastly what hub kit would be needed. If one is needed ?

Thank You in advance.

[Craig729]

I just replaced mine and still having issues, I got mine at a boat place, it was 300, on Amazon they were 129, the one I got has a plastic insert, I don't care for it much, but it is way cheaper if you have a spun hub again., I just bought an old Sea Ray with a 3.0 Mercury cruiser in it. After about an hour of running fine the boat would only run at a low speed, when I would try to accelerate it would sound like something slipped and it would stop moving forward, then I would go slow no problem, try to accelerate, done the same thing. I replaced the Hub and prop, took it out and it was doing good and after an hour or so, done the same thing again, it surely didn't spin the new hub or did it, is something slipping after warming up, I don't know a lot about boats, but I'm mechanically inclined and this does not make any sense. anyone have and good information. 

[sherman brown]

10 hours ago, Craig729 said:

I just replaced mine and still having issues, I got mine at a boat place, it was 300, on Amazon they were 129, the one I got has a plastic insert, I don't care for it much, but it is way cheaper if you have a spun hub again., I just bought an old Sea Ray with a 3.0 Mercury cruiser in it. After about an hour of running fine the boat would only run at a low speed, when I would try to accelerate it would sound like something slipped and it would stop moving forward, then I would go slow no problem, try to accelerate, done the same thing. I replaced the Hub and prop, took it out and it was doing good and after an hour or so, done the same thing again, it surely didn't spin the new hub or did it, is something slipping after warming up, I don't know a lot about boats, but I'm mechanically inclined and this does not make any sense. anyone have and good information. 

if your RPMs are going up but the boat isn't going faster it's a good bet the hub is bad. i can't think of any other reason that would account for this. I would think if it was the lower unit you could hear the gears grinding. the  1st thing I would do is put my spare prop on if I had one and see what it did. if you don't have a spare I would be getting one. but you can take it or ship it to a prop shop and have them check it and replace it if the hub is bad. if it has a flo torx hub kit you can tell if the corners are rounded off. if it's bad just get a new kit and replace the square insert.

[sherman brown]

On 4/30/2023 at 3:36 PM, Jedi said:

Looking to buy a new prop for the exiting prop  #48 78118 A40 P17

I/O 5.0 Mercruiser 95 Penn yan

is that a 15x17 or 14.5x17p ? And what is the inside diameter?

Thinking about going steel prop (3blades)if I can find one in the $300 range 🤣 If not going with a good aluminum prop. 

lastly what hub kit would be needed. If one is needed ?

Thank You in advance.

I don't know if this helps or not but I put a 13 1/4X17p high five prop on my mercruiser in a 21' Cobia boat. it had so much better hole shot handled so much better in rough water and in turnes. i would never put a 3 blade prop back on my boat. they are SS and cost over 500.00 new but you can usually find a used one in great like new condition for under 300.00 on eBay. I have been buying from them for the last 20 years and all the props I have bought used were as described. if anything you buy isn't as described you can file a dispute and get your money back.

 

but even if you don't want the high five you can probably find the prop you want for a lot less money getting a used prop off eBay.

[Bozeman Bob]

On 5/7/2023 at 8:52 AM, sherman brown said:

if your RPMs are going up but the boat isn't going faster it's a good bet the hub is bad. i can't think of any other reason that would account for this. I would think if it was the lower unit you could hear the gears grinding. the  1st thing I would do is put my spare prop on if I had one and see what it did. if you don't have a spare I would be getting one. but you can take it or ship it to a prop shop and have them check it and replace it if the hub is bad. if it has a flo torx hub kit you can tell if the corners are rounded off. if it's bad just get a new kit and replace the square insert.

Actually he could have a spun drive shaft  coupler. If OP marks the prop and includes the hub in the process all he has to do is run it , get it to " slip " then check the marks , if not lined up it's the prop . If still lined up the only thing left is the engine coupler to the drive shaft of the out drive.

[Bozeman Bob]

And you should be replacing the prop based on your RPM numbers , what the max RPM the motor is rated for vs what your seeing now with a average load in the boat . Without those numbers all your doing is guessing, and blowing money .